Analysis: The concept is very simple here. For Pre-intermediate, frequency is best practised using the present simple (expressing habits and routines is a good idea), and we can assume that they are already familiar with this, but will make mistakes, for example with questions and with the 3rd person singular.
never rarely sometimes often always
Lead in
Elicit using mime or pictures things you do every week/day, ask the students what they do, ask them if they do these things every day/week. “Do you play football every Monday?” Etc
Presentation
Start with ‘never’ and ‘always’ at 2 ends of a scale on the board. Elicit what they mean, and which means the most / least frequent. Ask for examples from the students about what they always or never do.
Put the other adverbs on the board and get pairs to sort the adverbs into order of frequency and then feedback.
Drill the words for pronunciation - don't forget to model first.
Elicit a sentence like "I play football on Saturdays" and get students to say where the adverb goes. And drill the sentence with the adverb in it.
Elicit the Q "How often...?" and drill this.
Write the question and an example response on the board to show where the adverbs are placed in the sentence.
Controlled practice
Jumbled sentences, give students exercise with sentences jumbled up and in pairs students need to put the sentences in the right order. This will check form of adverbs and question form.
Feedback
Try a few open pairs using ideas from the board, students ask and answer one at a time across the room.
Free practice
You will want to continue with the theme of habits and routines. In closed pairs, get students to interview each other. You could always assign characters to make it more interesting.